U.S. Pat. No. 6,595,500 discloses a handheld work apparatus with a diaphragm carburetor which comprises a pump which is to be actuated by the operator. The pump is configured as a flushing pump and delivers fuel from the fuel system into the fuel tank. The pump has a pump bellows. The pump bellows is fixed by a fastening section to the carburetor housing. That region of the pump bellows which adjoins the carburetor housing has a constant wall thickness.
In order, in particular in the case of pumps with a large pump bellows and correspondingly large delivery volume, to achieve resetting forces of a sufficient magnitude in order to reset the pump bellows from the actuated, pushed-in position into the unactuated position, it is known to insert a helical compression spring into the interior of the pump bellows, the helical compression spring assisting the resetting of the pump bellows. As a result, a sufficiently rapid resetting of the pump bellows is achieved even at low temperatures.